On August 20, 1970, a destructive
tornado
A tornado is a violently rotating column of air that is in contact with the surface of Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the ...
impacted the
Canadian
Canadians () are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of their being ''C ...
city of
Sudbury Sudbury may refer to:
Places Australia
* Sudbury Reef, Queensland
Canada
* Greater Sudbury, Ontario
** Sudbury (federal electoral district)
** Sudbury (provincial electoral district)
** Sudbury Airport
** Sudbury Basin, a meteorite impact cra ...
,
Ontario
Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
, killing six people and injuring 200 more in what became known as the Sudbury tornado. The tornado, which received a rating of F3 on the
Fujita Scale
The Fujita scale (F-Scale; ), or Fujita–Pearson scale (FPP scale), is a scale for rating tornado intensity, based primarily on the damage tornadoes inflict on human-built structures and vegetation. The official Fujita scale category is determ ...
, extensively damaged Sudbury and inflicted an estimated CA$17 million (1970 CAD) to the area. As of 2025, the tornado is the ninth deadliest in Canadian history.
Tornado summary

On the morning of August 20, a thunderstorm complex formed over eastern
Lake Superior
Lake Superior is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. Lake Michigan–Huron has a larger combined surface area than Superior, but is normally considered tw ...
and the
Upper Peninsula of Michigan
The Upper Peninsula of Michigan—also known as Upper Michigan or colloquially the U.P. or Yoop—is the northern and more elevated of the two major landmasses that make up the U.S. state of Michigan; it is separated from the Lower Peninsula of ...
ahead of a frontal trough. It moved eastward over
Georgian Bay
The Georgian Bay () is a large bay of Lake Huron, in the Laurentia bioregion. It is located entirely within the borders of Ontario, Canada. The main body of the bay lies east of the Bruce Peninsula and Manitoulin Island. To its northwest is t ...
and
Lake Huron
Lake Huron ( ) is one of the five Great Lakes of North America. It is shared on the north and east by the Canadian province of Ontario and on the south and west by the U.S. state of Michigan. The name of the lake is derived from early French ex ...
and then weakened. However, a storm cell within this complex gained unusual intensity near Elliot Lake. The tornado first touched down just west of that city in the wooded area of Matinenda Lake, according to a Canadian weather service report.
[
The tornado continued through forested areas and then touched the nearby town of Lively sometimes after 8 am EDT, tracking quickly eastward into the city and then hit the town of ]Copper Cliff
This is a list of neighbourhoods in the urban core of Greater Sudbury, Ontario. This list includes only those neighbourhoods that fall within the pre-2001 city limits of Sudbury — for communities within the former suburban municipalities, see ...
and Sudbury's neighborhoods of Robinson and Lockerby over the next ten minutes. The tornado then hit the community of Field
Field may refer to:
Expanses of open ground
* Field (agriculture), an area of land used for agricultural purposes
* Airfield, an aerodrome that lacks the infrastructure of an airport
* Battlefield
* Lawn, an area of mowed grass
* Meadow, a grass ...
, approximately 70 kilometres east of Sudbury, less than an hour later and dissipated north of Temiscaming, Quebec
Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...
, according to the report. The tornado corridor was 200 to 400 m wide in Sudbury area and its total length reached 275 km.[
The storm complex continued through North Bay and uprooted some trees in the wilderness but avoided any damage to the city.] It then tracked southeasterly toward Ottawa
Ottawa is the capital city of Canada. It is located in the southern Ontario, southern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Gatineau, Quebec, and forms the cor ...
, which led the federal government
A federation (also called a federal state) is an entity characterized by a political union, union of partially federated state, self-governing provinces, states, or other regions under a #Federal governments, federal government (federalism) ...
to order a precautionary shutdown of its offices in the capital, but the storm weakened around Chalk River
Chalk River (2016 population: 1029) is a community located within the town of Laurentian Hills in Renfrew County, Ontario, Canada. It is located in the Upper Ottawa Valley along Highway 17 (Ontario), Highway 17 (Trans-Canada Highway), inland ...
and only a few millimetres of rain fell on Ottawa when it reached that city.
Residents of the region had little warning of the storm, as the Sudbury Airport
Sudbury Airport or Greater Sudbury Airport is an airport in the Canadian city of Greater Sudbury, Ontario and is located northeast of the downtown area, on Municipal Road 86 between the communities of Garson and Skead. Although in many conte ...
did not yet have weather radar
A weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation (meteorology), precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern w ...
capable of detecting tornado rotation signal in the 1970's, and the day's only weather forecast had been for "showers." The first public indication of the tornado was instead a phone call to CKSO from a woman frantically reporting that her house was blowing away.
Aftermath
Both Joe Fabbro, the mayor of Sudbury, and Len Turner, the mayor of Lively, declared their respective communities disaster areas. Both the federal and the provincial governments immediately sent representatives to the city to assist, including provincial Attorney General Arthur Wishart
Arthur Allison Wishart, (June 11, 1903 – November 23, 1986) was a politician and in the Legislative Assembly of Ontario from 1963 to 1971. He was a Progressive Conservative member who served in the cabinets of John Robarts and Bill Davis.
...
, provincial Municipal Affairs Minister Darcy McKeough
William Darcy McKeough (January 31, 1933 – November 29, 2023) was a Canadian politician in Ontario. He was a Progressive Conservative member of the Legislative Assembly of Ontario from 1963 to 1978 who represented the ridings of Kent West ...
and federal Housing Minister Robert Andras
Robert Knight "Bob"
Andras
(February 21, 1921 -November 17, 1982) was a Canadian politician and businessman who served in multiple cabinet posts under Prime Minister Pierre Trudeau.
He was born February 21, 1921, in Lachine, Quebec. An ...
. With the company's operations temporarily disabled in the aftermath of the storm, Inco reassigned its employees to assist in rebuilding homes in Lively, which was then a company town
A company town is a place where all or most of the stores and housing in the town are owned by the same company that is also the main employer. Company towns are often planned with a suite of amenities such as stores, houses of worship, schoo ...
in which most homes were owned by Inco, rather than by private homeowners. In Sudbury, a $2 million relief fund was quickly set up by Sudbury City Council.
Despite the extent of the damage, however, many meteorologists initially resisted classifying the storm as a tornado; although the pattern of damage was consistent with tornadic activity, there were no confirmed reports of a visible funnel cloud
A funnel cloud is a funnel-shaped cloud of condensed water droplets, associated with a rotating column of wind and extending from the base of a cloud (usually a cumulonimbus or towering cumulus cloud) but not reaching the ground or a water su ...
. Although it is now generally understood that a tornado can occur without an identifiable funnel in certain weather conditions, that was not as widely accepted in the 1970s. It was not until 1972 that the Canada Atmospheric Environment Service published a final report confirming that a tornado had indeed taken place.
Six people died and 200 were injured in the tornado, which caused an estimated $17 million in 1970 (which is about $ million in ) in damage, including to Inco
Vale Canada Limited (formerly Vale Inco, CVRD Inco and Inco Limited; for corporate branding purposes simply known as "Vale" and pronounced in English) is a wholly owned subsidiary of the Brazilian mining company Vale. Vale's nickel mining and ...
's copper smelter
Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron, copper, silver, tin, lead and zin ...
in Copper Cliff. A pipeline carrying iron-nickel concentrate to the plant collapsed onto a train track below and caissed a derailment
In rail transport, a derailment is a type of train wreck that occurs when a rail vehicle such as a train comes off its rails. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway sys ...
when a train hit the collapsed pipe. The incident resulted in only minor injuries. The Inco Superstack
The Inco Superstack in Sudbury, Ontario, with a height of , is the tallest chimney in Canada and in the Western Hemisphere and the second-tallest freestanding chimney in the world, after the Ekibastuz GRES-2 Power Station, in Kazakhstan. It ...
, then under construction, swayed in the storm but was not heavily damaged. Six workers were on the construction platform at the time, all of whom survived.
Minor damage was also reported to the Big Nickel, with some pitting of the stainless steel panels as rocks and debris hit the monument, although that structure also survived. Damage was also reported to Memorial Hospital; Glad Tidings Tabernacle; and over 300 homes in Lively, Sudbury, and Field. Some streets in the affected neighbourhoods were flooded by up to a foot of water, and electrical and communications infrastructure was heavily damaged. For several days after the storm, amateur radio
Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emer ...
remained the only reliable method of communication into and out of the city. In Field, a lumber mill
A sawmill (saw mill, saw-mill) or lumber mill is a facility where logs are cut into lumber. Modern sawmills use a motorized saw to cut logs lengthwise to make long pieces, and crosswise to length depending on standard or custom sizes (dimens ...
, which was the town's primary employer, was heavily damaged, and a church roof was ripped off just minutes after parishioners had left the building after the end of the morning mass.
See also
* List of tornadoes and tornado outbreaks
These are some notable tornadoes, tornado outbreaks, and tornado outbreak sequences that have occurred around the globe.
# ''Exact death and injury counts are not possible; especially for large events and events before 1955.''
# ''Prior to 1950 i ...
* List of North American tornadoes and tornado outbreaks
These are some notable tornadoes, tornado outbreaks, and tornado outbreak sequences that have occurred in North America.
#''The listing is U.S.-centric, with greater and more consistent information available for U.S. tornadoes. Some North America ...
* List of Canadian tornadoes
This page lists tornadoes and tornado outbreaks which have touched down in Canada before the year 2000. On average, there are around 80 confirmed and unconfirmed tornadoes that touch down in Canada each year, with most occurring in the southern ...
References
{{1970 tornado outbreaks
Tornadoes of 1970
1970 in Ontario
1970
Events
January
* January 1 – Unix time epoch reached at 00:00:00 UTC.
* January 5 – The 7.1 1970 Tonghai earthquake, Tonghai earthquake shakes Tonghai County, Yunnan province, China, with a maximum Mercalli intensity scale, Mercalli ...
History of Greater Sudbury
August 1970 in Canada